Displays with touch function (i.e., touch displays) are more and more widely used. As an important form of touch displays, capacitive touch displays is provided with a plurality of drive electrodes (Tx) and sense electrodes (Rx) being disposed as intersecting each other, and capacitors are formed at adjacent positions of the two kinds of electrodes. Each of the drive electrodes apply drive signals by scanning, thus a sense signal is generated on a corresponding sense electrode. When a touch happens, a human body or a touch pen gets close to the touch area, affecting capacitors between the two kinds of electrodes in the touch area, causing change in the sense signal of the corresponding sense electrode, thereby deciding the touch position.
To prevent the electrodes from affecting the display, conventional drive electrodes and sense electrodes are made of transparent conductive materials such as tin indium oxide (ITO). However, the touch effect is compromised due to high resistance of ITO. Due to the above fact, metal mesh technology is developed, which fabricates the drive electrodes and/or sense electrodes with low resistance metal materials (such as silver, aluminum, copper, molybdenum, niobium or alloys thereof). As these metals are not transparent, they are made into a mesh.
A metal mesh touch substrate is illustrated in FIGS. 1 to 3, which may be an outmost protective plate of a display panel, with a touch structure thereof disposed at a side (facing the display panel) of a substrate 9. Black matrix is disposed around the perimeter of substrate 9 and configured for blocking leads of the touch structure (not illustrated in the drawing). The leads are disposed at a side of the black matrix further away from the substrate 9 (thus the leads are blocked by the black matrix when viewed from the side closer to the substrate 9) and configured for connecting drive electrodes 1 and sense electrodes 2 to a sense chip. A plurality of drive electrodes 1 disposed along the row direction (horizontally) and sense electrodes 2 disposed along the column direction (vertically) are disposed at the middle part of the substrate 9. Herein, each of the drive electrodes 1 comprises a plurality of rhombic drive metal meshes 11 disposed in one row, and adjacent drive metal meshes 11 are connected directly through the connection portion 12; each of the sense electrodes 2 comprises a plurality of rhombic sense metal meshes 21 disposed in one column, the sense metal meshes 21 are disposed on a same layer as the drive metal meshes 11, and adjacent sense metal meshes 21 are connected through the connection bridge 22. Herein the connection bridge 22 may be made of tin indium oxide (i.e., ITO bridge). Herein, the drive metal meshes 11, the sense metal meshes 21 and the connection portion 12 are all disposed on the substrate and formed simultaneously, with an insulation layer 4 overlaying thereon. The connection bridges 22 are disposed on the insulation layer 4 and connected to the sense metal meshes 21 through via holes in the insulation layer 4, thereby preventing the conduction between the drive electrodes 1 and the sense electrodes 2 at the overlaying positions. The connection bridges 22 are actually disposed above the insulation layer 4 and on a different layer from the metal meshes and the connection portion 12. However, as the insulation layer 4 is transparent, the connection bridges 22, metal meshes and connection portions 12 are visible simultaneously in the top view.
In the above example, both the drive metal meshes 11 and the sense metal meshes 21 are rhombic, and they may be of other shapes such as strip and the like, as long as they can respectively form the drive electrodes 1 and the sense electrodes 2 which intersect each other, and capacitors can be formed at adjacent positions of the metal meshes of two different electrodes. Such alternative shapes will not be elaborated herein.
It is seen from the above that the touch structure of metal mesh touch substrate is disposed on a single substrate, which belongs to an OGS (One glass solution) mode and is beneficial to reduce the thickness of the touch display. Meanwhile, the electrodes of the touch structure are disposed in the same layer, thus only four fabrication processes are needed when fabricating the touch structure: forming the black matrix, forming the metal layer (including the drive metal meshes 11, the sense metal meshes 21 and the connection portion 12), forming the insulation layer 4 having via holes, and forming the connection bridge 22.
The inventor finds that the conventional technology has the following problems: the adjacent sense metal meshes 21 are connected to each other through the connection bridges 22, which will inevitably generate a stacked structure at the position of bridge connection, easily causing problems such as bad anti-ESD performance and visibility of the bridge connection spots. Moreover, the fabricating process of the touch substrate is relatively complicated.